1. Field of the Invention
This invention is directed to an automatic hot needle station in polymer composition material bag manufacturing equipment for securing a stack of wicketed bags together by clamping the lips of the stack and penetrating the lips with a hot needle for tack-welding the bags together.
2. Description of the Prior Art
Automatic bag-making machines for making bags out of synthetic polymer composition material are well-known in the art. Such machines receive polymer composition film, such as polyethylene film, and perform the necessary operations on the film to produce a new bag. Often bag making comprises folding the film and sealing several edges. A common bag is folded over, and the sides are welded with one of the open edges extending beyond the other to form a lip. This lip is helpful in bag filling and handling and often contains wicket holes for handling the bags by wicketing as they are produced. In the handling of these bags from the bag-making machine, automatic wicketing equipment is employed. Such wicketing equipment includes a pair of wicket fingers and means for positioning the newly created bag with its holes engaging on the wickets. Such a structure is shown in Tonus U.S. Pat. No. 3,894,636.
In removal from the wickets, it is customary for the operator to manually insert wires through the wicket holes parallel to the wickets for the handling of a stack of bags. This manual effort requires additional labor time and is especially not advantageous in those cases where the bag-filling machine cannot employ a stack of bags which have wires through the wicket holes. If there is no restraint for a stack of bags, the bags can be misaligned or even dropped because of the slippery character of the bag material.
While it is known that the bag material can be welded together and, in fact, the bag-making machinery employs the weldability of the polymer composition material to seam up the bag, the employment of automatic equipment for attaching the bags together in a stack by means of a hot needle device has not been previously achieved.